ZX-128 broke down

Help anyone in any way you can. One person burned Speck, instead of 5v he supplied 12v (the wires were mixed up). As a result, it burned out: the processor, half of the VG (reads, but does not write),
memory, the AC remained intact, I don’t know about the ROM (there is nowhere to check).
I changed the processor, replaced all the memory, took out a test ROM.
I turn it on, there is a normal border on the screen, and in the center on a white background there are 4 black
parallel stripes, wide at the top, then 2 narrow, wide again at the bottom.
When you take out the ROM and processor, nothing changes.
Tell me where to dig next?
Thanks in advance!

All the best, All!
With best wishes *** Sergey *** !